White‐light emission and red scintillation from Mn ²⁺ ions single‐doped aluminum‐silicate glasses

Abstract A series of Mn ²⁺ single‐doped 0.2Gd ₂ O ₃ ‐0.2Al ₂ O ₃ ‐0.6SiO ₂ (GAS: xMn ²⁺ ) glasses with Si ₃ N ₄ as reducing agent were prepared. The presence of [SiO _4‐x ] defects and Mn ²⁺ ions was determined from the absorption and excitation spectra of the glasses. With the increase of Mn ²⁺ concentration, the intensity of blue emission decreases, while the intensity of red emission increases. The color coordinate of GAS: 6Mn ²⁺ glass is (0.264, 0.226). The lifetime of the glasses was tested. Under the monitoring of 440 nm, the fast components (τ _f ) are between 17 and 85 μs, and the slow components (τ _s ) are between 200–650 μs. The former belongs to [SiO _4‐x ] defects, and the latter is [ ⁴ E(G), ⁴ A ₁ (G)]→ ⁶ A ₁ (S) transition of Mn ²⁺ ions. Under the monitoring at 630 nm, the τ _f are between 110 and 300 μs, and the τ _s are between 680 and 1220 μs, which are due to ⁴ T ₁ (G)→ ⁶ A ₁ (S) transition of Mn ²⁺ ions and Mn ²⁺ pairs, respectively. The energy transfer mechanism of [SiO _4‐x ] defect→Mn ²⁺ ions are explained. The efficient [SiO _4‐x ] defect →Mn ²⁺ ions energy transfer process was demonstrated by time‐resolved photoluminescence, and the energy transfer efficiency is over 85%. The maximum photoluminescence quantum yield (PL QY) of the glasses can reach 15.87%. The thermal activation energy of the glasses was calculated. In addition, X‐ray excited red luminescence spectra and the mechanism of the glasses were investigated.